Refrigeration evaporator construction



Aug. 12, 1958 Filed Feb. 19, 1953 w. A. COLLINS ETAL 2,847,194

REFRIGERATION EVAPORATOR CONSTRUCTION 3 Sheets-Sheet 1 34 45 w 4 J 35 4z 44 3 Hill-2:. i 3:: il'fl==i lii "-i E ii 5 5i! Aug. 12, 1958 w. A. COLLINS ETAL 4 REFRIGERATION EVAPORATOR CONSTRUCTION Filed Feb. 19, 1955 s Sheets-Sheet 2 E E-E- INVEN 0R5 14 12/14 fiz /1 75, 21 4/11 Z Zaree/z Aug. 12, 1958 w. A. COLLINS ETAL 2,847,194

REFRIGERATION EVAPORATOR CONSTRUCTION Filed Feb. 19. 1953 s Sheets-Sheet z INVENTORS l Vzlzl" 6 76 Z! Zia/ 4755a 7' arZ/j nite States Patch 2,847,194 Patented Aug. 12, 1958 REFRIGERATION EVAPORATOR CONSTRUCTION William A. Collins and Edward D. Floreen, Dowagiac, Mich., assignors to Rudy Manufacturing Company, Dowagiac, Mich., a corporation of Michigan Application February 19, 1953, Serial No. 337,762

1 Claim. (31. 257-256) This invention relates to heat exchangers and, more particularly, to an improved evaporator adapted for use in refrigerating systems and an improved method of construction.

In the past, the usual practice in the refrigeration industry was to construct each evaporator compartment from a single metal sheet. Each sheet was shaped to form the top, bottom and side walls of an evaporator compartment of a particular size and shape and a refrigerant conduit was built into or coiled around the periphery of the compartment and bonded in heat conducting relation to the top, bottom and side walls along substantially the entire length of the conduit. Such practices are objectionable in the small quantity production of evaporators since production equipment must be provided which can bend and shape the various sizes of metal sheets and the setup of such equipment must be changed for each size or type of evaporator compartment with a consequent loss of time and labor. Because of the coiling of the conduit around the compartment, the mass or weight of the material which must be brazed is relatively large with a gonsequent increase in the cost of the brazing operation.

In practicing the present invention, the evaporator compartment, which was formerly constructed of a single sheet of metal shaped in the aforementioned manner, is constructed of separate flat plates and panels. Refrigerant conduits are bent into serpentine form and bonded in heat conducting relation, as by brazing, to the plates only. Such a construction permits the plates having the serpentine tubing bonded thereto to be used as the side walls of an evaporator compartment and the length and size of the compartment may be varied by changing the length of the top and bottom panels without changing the tooling for making the plates. Such a construction also permits the aforementioned plates to be used as the top and bottom walls of an evaporator compartment and the height and size of the compartment may be varied by changing the height of the side panels only. Not only does this reduce the mass or weight of the material which must be brazed to a minimum with a resultant reduction in the cost of the brazing operation but such a construction also reduces the tooling cost, since substantially all of the components of the evaporator may be made on astandard press brake with a standard punch and notch setup or a standard die set. Furthermore, the reduced cost of such tooling makes such a coni struction pro-eminently suited for small quantity production of evaporators.

Accordingly, the principal objects of the present invention are to overcome disadvantages inherent in conventional heat exchanger constructions; to provide an improved method of constructing an evaporator compartment which reduces the weight of material which must be brazed to a minimum and also reduces the tooling cost; to form an evaporator compartment of separate top, bottom and side pieces which may be assembled to form compartments of various sizes and shapes; to provide an improved evaporator that may be easily and quickly secured in a refrigerating device in either a vertical or horizontal position; to provide an improved evaporator incorporating means adapted to obviate the tendency of the liquid refrigerant to become entrained in the suction conduits of the refrigerating system; and in general, to provide an improved evaporator that is simple in construction, economical to manufacture, durable, efiicient and reliable in operation.

The above as well as other objects and advantages will become apparent from the following description, taken in conjunction with the accompanying drawings wherein:

Figure 1 is a top plan view of a heat exchanger showing one form of the invention;

Fig. 2 is a front elevational view of the structure illustrated in Fig. 1;

Fig. 3 is an enlarged, broken, end elevational view of a portion of the structure illustrated in Fig. 1, taken on the line 3-3 thereof;

Fig. 4- is a side elevational view of a heat exchanger illustrating another form of the invention;

Fig. 5 is a front view of the structure illustrated in Fig. 4;

Fig. 6 is a view of structure similar to that illustrated in Fig. 1, showing still another form of the invention;

Fig. 7 is a front view of the structure illustrated in Pig. 6; and

Fig. 8 is a broken, end elevational view of a portion of the structure illustrated in Fig. 6, taken on the line 8-8 thereof.

Referring to the drawings, one form of the invention is illustrated in Figs. 1, 2 and 3 and includes a pair of spaced, horizontally extending plates 10 and 12, the upper plate 10 having a downwardly deflected edge portion forming a recess 14. A pair of fluid conducting conduits 16 and 18 of serpentine form are provided having straight portions 20 connected by integral, reversely bent end portions 22. The fluid conducting conduits 16 and 13 are bonded to the plates 10 and 12, respectively, in heat conducting relationship, as by brazing. The tubes forming the conduits may be D-shaped in cross-section as described in the application for Letters Patent of Thomas H. Polad, Serial No. 179,469, filed August 15, 1950, now Patent No. 2,691,813 granted October 19, 1954, and the tubes may be bonded to the plates 10 and 12 in the manner disclosed in such application.

A pair of side panels 24 and 26, having extending flanges 28 and 30, overlap the ends of the plates 10 and 12 and are welded or otherwise secured thereto so as to form the compartment of an evaporator which may be utilized as a freezing unit in a refrigerator. It will be appreciated that the side panels 24 and 26 may have the flanges 28 and 30 formed thereon with the use of a minimum amount of tools and that the height and size of the compartment may be varied by varying the height and width of the panels. It will also be appreciated that such a construction reduces the mass or weight of material which must be brazed to a minimum since the conduits 16 and 18 are brazed to the plates only.

The sinuous conduits 16 and 18 are interconnected by a cross-over tube 32 at the forward end while a crossover tube 34- interconnects the rear end of the bottom conduit 18 with an accumulator 36 disposed in the recess 14.

The accumulator 36 is constructed from a cylindrical sleeve 38- having caps and 42 brazed or otherwise secured thereto. The crossover tube 34 extends through the cap 4i? while a tube 44 extends through the cap 42, the tubes 34 and 44 being attachable to the caps 40 and 42 respectively, by brazing. The inner end of the tube 44 is bent upwardly, as at 46, so as to extend into the I w I Quit top portion of the accumulator 36 above any liquid contained therein. The accumulator 36 is retained in the recess 14 and the tubes 34- and 4d are secured to the top plate it) by suitable clips 48. A tube Si is connected to the opposite end ofthe serpentine conduit 16 from that to which the cross-over member 32' is connected and serves to connect the serpentine tubing to the liquid side of the refrigerating system while the tube conmeets the accumulator to the gaseous side of the refrigerah ing system.

in the operation of the refrigerating system, a portion of the refrigerant may be in the liquid state and a portion in the gaseous state when the refrigerant reaches the accumulator 36. The;above described arrangement permits the refrigerant which is in the gaseous state to flow through the opening in the upwardly exten-din g end portion of the tube 44 while the portion of the refrigerant in the liquid state remains in the accumulator to further reduce the ambient temperature. Such. a construction is relatively inexpensive and increases the etficiency of the evaporator by preventing the liquid refrigerant from becoming entrained in the suction portion of the refrigerating system.

The form of the invention i'lustrated in Figs. and 5 incorporates a pair of plates 52 and 54 having sinuous refrigerant conduits 56 and 53 bonded thereto. The plates 52 and Sd'are similar to the plate 12 in the form of the invention previously described but in this form of the invention, the plates 52 and 5d are disposed in spaced, substantially vertical parallel planes. Top and bottom panels 6-9 and 62, having extending flanges 6 6 and 66, overlap the top and bottom portions of the plates 52 and 5 and are spot-welded or otherwise secured thereto to form the compartment of an evaporator. it will be appreciated that the width of the top and bottom panels 66 and 62 may be varied to form compartments of various widths and the flanges 64 and 66 may he formed on the top and bottom panels with a minimum amount of tooling.

The conduits 56 and 58 are interconnected by a crossover tube 63 at the lower end while the distal end of the conduit 58 is connected with an extension member '79 which serves to connect the conduits to the liquid side of the refrigerating system. An accumulator "1'2, which is constructed from a cylindrical sleeve 74- having end caps 76 and 78 brazed or otherwise secured thereto, is secured to the outer surface of the plate 52 by suitable clips Eltl. The accumulator 72 extends upwardly and rearwardly and. the upper end of the conduit 56 extends through the cap '76 at the lower end of the accumulator while a tube 32 extends through the cap 73 and serves to connect the accumulator to the gaseous side of the refrigerating system. Such a. construction obviates the tendency of the liquid refrigerant to become entrained in the suction conduits of the refrigerating system since the gaseous refrigerant will rise to the upper end of the accumulator and flow through the tube 32 while the liquid refrigerant remains in the lower end portion of the accumulator.

A plurality of horizontally extending angle pieces 34 are secured to the inner sides of the plates 52 and 54 by rivets 86 or other suitable means and serve to support shelves or trays (not shown).

In the form of the invention illustrated. in Figs. 6, 7 and. 8, a pair of spaced, horizontally disposed plates 99 and 5'2 are providedhaving fluid conducting conduits 94- and 96 of serpentine form bonded thereto in the manner previously described. The upper plate 99 is provided with an upwardly deflected edge portion forming a recess 98 while downwardly directed flanges 1G9 and ltlZ are formed at opposite ends of the upper plate. A pair of side panels 104 and 106, having flanges Hi8 and 110 formed thereon, are joined to the ends of the plates. The flanges 1% at the lower end portions of the panels 4 overlap, and are welded or otherwise secured to, the ends of the plate 92 while the flanges 100 and 102 on the plate abut the inner surfaces of the panels 194 and 106 intermediate the ends thereof and are spot- Welded or otherwise secured thereto to form an evaporator compartment which may be secured to a horizontally extending surface in a refrigerator by the flanges 110. it will be appreciated that in this form of the invention the size and shape of the compartment may be varied by chan 'ng the position at which the flanges and are fixed to the side panels-as well as by varying the height of the side panels.

in this form of the invention the sinuous conduits 94 and Q6 are disposed on the lower sides of the plates 90 ad 5 2 and since the upper portions of the panels 164 .d .166 project upwardly beyond the plate 90, both the plates 9t} and 92 may be used as shelves.

The forward ends of the sinuous conduits 94 and. 96 are interconnected by a cross-over tube 112 which extends through an aperture in the panel 16.4 while a cross-over tube 114 extends through an aperturein the ear portion of the panel M4 and interconnects the opposite end of the lower conduit 96 to an accumulator 116 disposed in the recess 98. The accumulator is constructed in the manner similar to the accumulator described in the form of the invention shown in Figs. 1, 2, and 3 and'the opposite end of the accumulator is connected to the gaseous side of the refrigerating system by a tube 113, the inner end portion of the tube being bent upwardly to extend above any liquid contained in the accumulator. The accumulator is retained in the recess 98 and the tubes 114 and 118 are secured to the top plate 5%? by suitable clips 12% while a tube 122 is connected to the opposite end of the conduit 9 's from that to which the cross-over member 112 is connected and is employed for connecting the conduit 94 to the liquid side of the refrigerating system.

Substantial advantages are provided by the method employed in the construction of the evaporator. The reduction of the material which must be brazed to a minimum reduces the cost of the evaporator and the utilization of separate plates and panels to form the top, bottom and side walls of an evaporator compartment facilitates the assembly of compartments of various sizes and shapes. A further advantage is realized in the reduction of tooling costs since the plates and panels may be fabricated and shaped with standard equipment.

What is claimed is:

A heat exchanger comprising a pair of spaced flat plates, a pair of conduits of serpentine form, one of said conduits bonded to each of said plates, a pair of spaced panels which may vary in length to vary the height of the exchanger joined to said plates to form a compartment, said panels being joined to the edges of said plates by inturned flanges which may vary in length to determine the position of the side panels outwardly of the edges of the plates, and a separate attachable crossover conduit member interconnecting said conduits, said cross-over conduit member being attachable to said conduits.

References Cited in the file of this patent UNITED STATES PATENTS l,374,905 Casey et al. Apr. 19, l92l 1,757,041 Gail et al. May 6, 1930 2,569,011 Moore May 23, 1950 2,515,972 White et a1. July 18, 1950 2,517,212 Kafer et al. Aug. 1, 1950 2,597,267 Shoemaker et al Nlay 20, 1952 2,622,412 Staegler Dec. 23, 1952 2,682,158 Powell June 29, 1954 

